1. Field of the Invention
The present invention relates to novel cosmetic compositions for topical application, for the artificial tanning of the skin (such compositions sometimes being referred to as self-tanning compositions), to a process for the formulation thereof and also to the use of same for the cosmetic application indicated above.
The present invention more especially relates to artificial suntan compositions having improved activity and which comprise specific oil-in-water emulsions (in a cosmetically acceptable vehicle or carrier) containing dihydroxyacetone as the self-tanning agent.
2. Description of the Prior Art
It is known to this art that dihydroxyacetone, or DHA, is a particularly advantageous compound which is currently employed in cosmetics as an agent for the artificial tanning of the skin. When applied to the skin, especially to the face, it elicits a tanning effect, the appearance of which is similar to that which may result from prolonged exposure to the sun (natural tan) or under a UV lamp. When used as such, moreover, it presents the advantage of totally avoiding the risks of skin reaction which are generally associated with the aforesaid prolonged exposures (erythema, burns, loss of suppleness, appearance of wrinkles, premature aging of the skin, and the like).
For a variety of reasons, especially associated with superior comfort in use (softness, suppleness, ease of application) modern self-tanning compositions are most often produced in the form of an oil-in-water emulsion (i.e., a vehicle comprising an aqueous dispersing continuous phase and an oily dispersed discontinuous phase) into which the dihydroxyacetone has been introduced at various concentrations. The dihydroxyacetone, because of its hydrophilicity, is present in the aqueous phase of the emulsion. In these conventional emulsions, which additionally contain emulsifiers (or surfactants) and optional, conventional cosmetic additives and adjuvants, such as fragrances, dyes or preservatives, the size of the globules constituting the oily liquid phase is generally greater than several microns.
However, one of the disadvantages of the known self-tanning compositions of the above type (O/W emulsion containing DHA) is that the intensity of the coloration obtained on the skin and/or the rapidity with which this coloration develops, is/are ofttimes inadequate.